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<p>The seismic risk potential is also profoundly influenced by the frequency-dependent attenuation characteristics of seismic waves. The Northwest Himalaya, situated in the India–Eurasia collision zone, faces significant seismic risk, heavily influenced by the dissipation of seismic waves at various frequencies. This region has experienced many destructive earthquakes of varying magnitudes, highlighting its seismic activity. Prominent events are the recent highly destructive <i>M</i><sub><i>w</i></sub> 7.6 Kashmir earthquake of 2005 and the last century <i>M</i><sub><i>w</i></sub> 7.8 great Kangra earthquake of 1905. Our research focused on the P-wave (<i>Q</i><sub><i>α</i></sub>), S-wave (<i>Q</i><sub><i>β</i></sub>), and coda wave (<i>Q</i><sub><i>c</i></sub>) attenuation properties by analyzing data from 831 micro-to-moderate earthquakes (magnitude range 2.5–5.0) recorded by 20 seismic stations. The data recorded from 2008 to 2015 are used to obtain attenuation at 5 central frequencies between 1.5 and 12 Hz. Our findings reveal critical structural heterogeneities impacting seismogenesis, which are vital for assessing subsurface attenuation properties. This understanding is essential for evaluating seismic risks and the potential consequences on the densely populated regions of the world. We developed a model demonstrating the relationship between structural variations and the seismic attenuation characteristics of different geotectonic blocks, highlighting the uneven distribution of fault systems across the NW Himalayas. Seismic risk varies across geotectonic blocks, with changes in seismic attenuation from south to north. Factors such as fault types, material compositions, and levels of strain energy are associated with these structural disparities. The Higher Himalaya, characterized by crystalline rocks, has the lowest seismic attenuation for the present data, making it more susceptible to stronger earthquakes. Conversely, the Lesser Himalaya exhibits comparatively a slightly low earthquake risk due to higher attenuation levels. Similarly, attenuation indicates a slightly low risk for the Sub-Himalaya compared to the Indo-Gangetic Plain (IGP), owing to its comparatively high seismic attenuation. This understanding is crucial for developing effective earthquake resilience strategies in this section of the Himalayas and IGP.</p>

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Seismic risk potential of NW Himalaya: Inferences based on attenuation model

  • 期刊论文

  • 发表日期：

    2025年5月8日

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  • Vandana,
  • Naresh Kumar

摘要

The seismic risk potential is also profoundly influenced by the frequency-dependent attenuation characteristics of seismic waves. The Northwest Himalaya, situated in the India–Eurasia collision zone, faces significant seismic risk, heavily influenced by the dissipation of seismic waves at various frequencies. This region has experienced many destructive earthquakes of varying magnitudes, highlighting its seismic activity. Prominent events are the recent highly destructive Mw 7.6 Kashmir earthquake of 2005 and the last century Mw 7.8 great Kangra earthquake of 1905. Our research focused on the P-wave (Qα), S-wave (Qβ), and coda wave (Qc) attenuation properties by analyzing data from 831 micro-to-moderate earthquakes (magnitude range 2.5–5.0) recorded by 20 seismic stations. The data recorded from 2008 to 2015 are used to obtain attenuation at 5 central frequencies between 1.5 and 12 Hz. Our findings reveal critical structural heterogeneities impacting seismogenesis, which are vital for assessing subsurface attenuation properties. This understanding is essential for evaluating seismic risks and the potential consequences on the densely populated regions of the world. We developed a model demonstrating the relationship between structural variations and the seismic attenuation characteristics of different geotectonic blocks, highlighting the uneven distribution of fault systems across the NW Himalayas. Seismic risk varies across geotectonic blocks, with changes in seismic attenuation from south to north. Factors such as fault types, material compositions, and levels of strain energy are associated with these structural disparities. The Higher Himalaya, characterized by crystalline rocks, has the lowest seismic attenuation for the present data, making it more susceptible to stronger earthquakes. Conversely, the Lesser Himalaya exhibits comparatively a slightly low earthquake risk due to higher attenuation levels. Similarly, attenuation indicates a slightly low risk for the Sub-Himalaya compared to the Indo-Gangetic Plain (IGP), owing to its comparatively high seismic attenuation. This understanding is crucial for developing effective earthquake resilience strategies in this section of the Himalayas and IGP.